Hand-held hair dryers are probably one of the most widely used electrical appliances known to-date and they can be found in almost every home in the developed world. Because of its usually high power consumption rate of 1-2 kW, a hair dryer is usually equipped with a flexible power cord for connection to the mains power supply. While a long power cord is desirable to provide high mobility so that the hair dryer can be used at a distance from the mains outlet, an excessive length of un-restrained power cord accessible to young children is however already known to be a source of potential domestic hazards.
Furthermore, it is well known that the power cords from adjacently stored corded appliances tend to entangle together and it would be difficult to separate the entangled power cords. As there are ever-increasing varieties of corded electrical appliances, this is an annoying phenomenon which a designer of electric appliances need to consider in the development of new appliances.
To alleviate the aforementioned problems, it is desirable that a built-in power cord storage device is provided on a hair dryer so that the excessive length of power cord can be restrained and stored on the dryer, especially when the dryer is not in use. In addition, a desirable power cord storage device should preferably provide a controlled release of the stored power cord so that only a desired length of cord is released while the remaining portion is kept on the dryer.
Portable hair dryers with retractable power cord storage devices are already known. U.S. Pat. Nos. 4,528,440 and 5,784,800 issued respectively to Ishihara and Santhouse et al. represent better known types of them.
The former type is characterized by a laterally mounted power cord storage device which results in a lack of symmetry about the vertical plane. This lack of symmetry leads to a two-fold disadvantage--a user would have to hold the dryer firmly upright to prevent tilting and that left- and right-hand versions would have to be supplied to better suit different users.
The latter type is characterized by a cord storage reel which is mounted in coaxial alignment with the elongate barrel inside the housing of the dryer. A main disadvantage of this latter arrangement is that many unsightly air vents are required on the sides of the hair dryer in order to provide alternative ventilation paths when the conventional air-ventilation paths, formed between ventilation holes at the rear of the hair dryer and the barrel exit, are blocked by the power cord being carried on the cord reel. The presence of such additional ventilation holes also means that water drops can get in more easily and cause electric faults.
As a conventional hair dryer is usually provided with electric coil heaters which are turned on or off by a toggle switch, potential fire hazards are often a major concern for families with young children who may accidentally or deliberately turn hair dryers on and leave them on. This is especially dangerous when the whole length of power cord is being stored on the cord reel inside the barrel, thereby substantially blocking the ventilating paths.
Furthermore, the affinity of blown dried hair for dust is another known shortcoming of conventional portable hair dryers with which designers of hair dryers need to be concerned if a more useful appliance is to be made available to the public.